The present invention relates to the field of gas delivery systems, in particular, scrubbing of leaked process gas from gas panels.
A conventional processing system includes a processing chamber, sources of processing gases and a gas panel to control the flow of the processing gases from the sources to the processing chamber. One of the common uses of the gas panels is in the fabrication facilities. Gas panels are equipped with Mass flow controllers (MFC) and air operated valves and their arrangement is dependent on a particular application. An MFC is used to measure and control the flow of gases or fluids on the gas panels. This is further explained with the help of FIG. 1 for a conventional gas panel.
FIG. 1 illustrates an example arrangement for a conventional gas panel.
As illustrated in the figure, conventional gas panel 100 includes a plurality of MFC 102, a plurality of gas valves 104, and an exhaust system 106.
Each of MFC 102 receives a gas supply from a gas source via a respective gas supply line 108. A gas source may provide a gas or, more generally speaking, a fluid. Each gas supply line may carry a different respective gas or a fluid to a respective MFC 102. Each MFC 102 is designed and calibrated to control the flow of its received gas. In the example arrangement of FIG. 1, seventeen MFCs are arranged to receive seventeen different gas supplies from gas sources via inlet valves (not shown). Out of the different gases feeding in to gas panel 100, some may be process gases or compressed dry air (CDA) or inert gases as required by a particular application.
Each MFC 102, as shown by gas supply lines 110, feeds a respective gas valve. Each gas valve 104 can be an on/off valve or a controllable valve in order to control the flow of gas through it. Gas valve 104 further supplies gas to a process chamber (not shown) via supply lines 112.
Exhaust system 106 is used to extract any trapped gases within gas panel 100 via an outlet 114. Scrubber exhaust is an example, where unwanted gases are removed from the exhaust streams.
Some of the processing gases going in to MFC 102 via gas supply lines 108 are hazardous, e.g., flammable and/or poisonous. If any of the processing gases leak within gas panel 100, such as a result of a break in a processing gas line break, the leaked processing gas may pool within gas panel 100. The pooled processing gas creates a hazardous situation. This is further explained with the help of FIG. 2.
FIG. 2 illustrates a broken gas supply line between a MFC and a gas valve.
FIG. 2 illustrates a processing gas 206 being fed to a MFC 202. A gas supply line 208 between MFC 202 and a gas valve 204 is broken, resulting in a leaked gas 212. In one embodiment, MFC 202 and gas valve 204 are part of gas panel 100. In this example, leaked gas 212 gets pooled in gas panel 100, which must be removed. There may be dead space within gas panel 100, which may cause a hazardous situation. A dead space is a space within gas panel 100 in which there is little or no movement of the gas, e.g., no air current. Accordingly, leaked gas 212 may pool in such dead space.
Exhaust system 106 helps to extract gases from within gas panel 100 to address the leaked processing gases in gas panel 100. This is further explained with the help of FIG. 3.
FIG. 3 illustrates a conventional gas panel 300 with a broken processing gas line 208.
Conventional gas panel 300 includes all the components of conventional gas panel 100 except MFC 202 and gas valve 204. As illustrated in the figure, gas supply line 208 between MFC 202 and gas valve 204 is broken, resulting in leaked gas 212. Leaked gas 212 is trapped in dead zones within gas panel 300 as indicated by dotted lines. Gas panel 300 may include a mechanism to indicate the presence of unwanted gases inside gas panel 300. The amount of leaked gas 212 is concentrated in some pockets within gas panel 300, which may be more than the minimum allowable amount as per the safety requirements. Some of the processing gases are toxic and flammable; therefore, leaked gas 212 must be removed to avoid a hazardous situation.
Conventional gas panel 300 uses exhaust system 106 to extract gases from within gas panel 300. In many cases, exhaust system 106 may run continuously at its full capacity, and still be unable to remove the leaked gases pooled inside gas panel 300. In other words, in some instances exhaust system 106 does not work efficiently in performing its intended operation, whereas in other instances, exhaust system 106 does not perform its intended operation.
In case the amount of toxic gases within gas panel 300 is more than the minimum allowable amount, the conventional systems may increase the exhaust and scrubber to take care of the leaked gases. However, these conventional systems are not efficient at scrubbing leaked processing gas 212 from gas panel 300.
Additionally, scrubber exhaust from the gas panels adds to higher facilitation cost and power consumption. Most of the fabrication facilities, where the gas panels are used, are constantly requiring lowering the cost of operation, facilitation cost, power consumption, and building capital expenses. In addition, human safety shall be improved by minimizing the potential risk of ignition.
What is needed is an efficient system and method for scrubbing leaked processing gas from a gas panel.